FIG. 13 is a perspective view of a cellular phone with a conventional folding structure, and FIG. 14 is a perspective view of the conventional cellular phone folded, as viewed from the rear side. The cellular phone is configured with a hinge (5) foldably connecting a first cabinet (9), which is provided with a display panel (91) that displays information, and a second cabinet (90), which is provided with operation keys (92). (See Japanese Patent No. 3093727.)
The first cabinet (9) is provided with a first inner case (1) in which the display panel (91) is installed, and a first outer cover (3) that covers the rear side of the first inner case (1). The second cabinet (90) is provided with a second inner case (2) in which the operation keys (92) are installed, and a second outer cover (4) that covers the rear side of the second inner case (2).
FIG. 8 is an exploded perspective view of the two conventional inner cases (1) and (2), and the two outer covers (3) and (4). The operation keys (92) are not shown in the figure, but the through-holes (93) into which the operation keys (92) are fitted are shown. An image control circuit (80) that changes the images of the display panel (91) is provided inside the first outer cover (3), and a system control circuit (81) that receives signals from the operation buttons (92) and issues signals to update the images in the image control circuit (80) is located inside the second outer cover (4). The image control circuit (80) and the system control circuit (81) are connected by a connection member (8) or a flexible substrate, electrical wiring or the like, and this connection member (8) is accommodated in the hinge portion (5).
FIG. 9 is an exploded perspective view of the conventional first and second inner cases (1) and (2), and FIG. 10 is a cross-sectional view through a vertical plane containing the F—F line in FIG. 9. Both inner cases (1) and (2), and both outer covers (3) and (4) are formed by injection molding of a synthetic resin. A first fitting portion (10) is provided at the end of the first inner case (1), and a second fitting portion (20) that fits into the first fitting portion (10) is provided at the end of the second inner case (2). The hinge portion (5) is constituted by the first fitting portion (10) and the second fitting portion (20).
The first fitting portion (10) is provided with a first tube structure (11), which is provided with a small aperture (14) that passes through the center of first tube structure (11), and spaced apart from a second tube structure (12) on the same line. The second fitting portion (20) is provided with a third tube structure (21) positioned on the outer side of the first tube structure (11), a first covering structure (23) positioned between the first tube structure (11) and the second tube structure (12), and a fourth tube structure (22) positioned on the outer side of the second tube structure (12). A second covering structure (13) is provided extending from the second tube structure (12) toward the first tube structure (11). The second covering structure (13) is substantially arc-shaped in profile (see FIG. 12), and is positioned in line with the first covering structure (23). The undersides of the first and second covering structures (23) and (13) are open.
Pivot shafts (51) are inserted from the outside of the third tube structure (21) and the fourth tube structure (22). Along the insertion directions of the two tube structures (21) and (22), the pivot shafts (51) are provided with a large-diameter portion (51a), a mid-size diameter portion (51b), and a small-diameter portion (51c).
As shown in FIG. 10, provided as openings in the third tube structure (21) and the fourth tube structure (22) are a large aperture (26), into which the large-diameter portion (51a) is fitted, and a mid-size diameter aperture (27), into which the mid-size diameter portion (51b) is fitted. The small-diameter portion (51c) fits into the small aperture (14) of the first tube structure (11) and the second tube structure (12).
The pivot shafts (51) pass through the large aperture (26) and the mid-size diameter aperture (27) of the third tube structure (21) and the first tube structure (11), and the fourth tube structure (22) and the second tube structure (12) from the outer sides of the second inner case (2), and by fitting stopper washers (52) at the tip of the small-diameter portions (51c) of the pivot shafts (51), both inner cases (1) and (2) are connected by the hinge (5).
FIG. 11 is a back side view of the two inner cases (1) and (2) of FIG. 8. The connection member (8) can pass underneath the first and second covering structures (23) and (13), which are shown shaded in FIG. 11. That is, the shaded portion forms a cut-out (50) of the hinge portion (5).
As shown in FIG. 8, a first protruding piece (35) protrudes from the bottom end of the first outer cover (3), and a second protruding piece (45) protrudes from the top end of the second outer cover (4). The first protruding piece (35) cover the lower part of the second covering structure (13), and the second protruding piece (45) covers the lower part of the first covering structure (23), thus forming an outer peripheral surface of the hinge portion (5), and accommodating the connection member (8) inside the hinge portion (5).
In the conventional structure, not only the two inner cases (1) and (2), but the first protruding piece (35) of the first outer cover (3), and the second protruding piece (45) of the second outer cover (4) constitute the outer peripheral surface of the hinge portion (5) (see FIG. 14). Consequently, lined up on the rear side of the hinge portion (5) are structural portions of the two inner cases (1) and (2), and the two outer cases (3) and (4). Conventionally, it has been usual to prevent the formation of a striped pattern by making the two inner cases (1) and (2), and the two outer cases (3) and (4) consistent with all being the same color.
However, in order to achieve design diversification and product differentiation, there is now a need for forming the two inner cases (1) and (2), and the outer covers (3) and (4) with different colors. With a conventional structure, attempting to form the inner cases (1) and (2) and the outer covers (3) and (4) with materials of different colors led to the deficiency of the hinge portion (5) being formed with a striped pattern. Specifically, if attempting to form the inner cases (1) and (2) in pink, and the outer covers (3) and (4) in white, the first protruding piece (35) and the second protruding piece (45) would be formed in white, and the first to fourth tube structures (11), (12), (21), and (22), as well as the first covering structure (23) and the second covering structure (13) would be formed in pink, and therefore the outer peripheral surface of the hinge portion (5) shown in FIG. 14 would become a striped pattern of white and pink, thus adversely affecting the attractiveness of the hinge portion (5) when viewed from the outside.
At this point, applying a color to the first protruding piece (35) and the second protruding piece (45) that is different from the color of the outer covers (3) and (4) is troublesome. Moreover, if applying a color to the first protruding piece (35) and the second protruding piece (45) with a coating or the like, there is the problem that the attractiveness becomes all the more adversely affected when the coating on the first protruding piece (35) and the second protruding piece (45) wears off, and their actual surfaces become exposed.
Also when the inner cases (1) and (2) and the outer covers (3) and (4) are formed with materials of different textures or patterns, there is the same problem of the hinge portion (5) becoming a striped pattern.
An object of the present invention is to provide a foldable portable terminal by which, even when the inner cases and the outer covers are formed with materials that have different visual qualities and feel, it is possible to make the hinge portion consistent with a material that has the same visual qualities and feel.